• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.744-750
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• 2015

The objectives of this study were to investigate soil chemical characteristics for forest rehabilitation and suggest management in abandoned coal mine areas in Boryeong City, Chungcheongnam-do. Total study sites were seven sites, and soil properties analyzed were soil pH, total organic carbon (TOC), total-N, C/N ratio, and available $P_2O_5$ (A.v. P). Average soil pH (range) was 5.9 (4.5~7.0). Three study sites (Samgwang, Shinsung1, and Shimwon1) showed lower soil pH than standard (pH 5.6~7.3) of Korea Industrial Standards (KS) for abandoned coal mine forest rehabilitation. Average contents of TOC, and total-N were 1.5% (0.1~4.7%), and 0.10% (0.03~0.23%), respectively. Five study sites where the collapsed time was less than 10 years (Wangjashingang, Wonpoong, Samgwang, Shinsung1, and Shinsung2) showed lower TOC level than standard of KS (more than 1.2%). Wangjashingang, Wonpoong, Samgwang, and Shinsung1 showed lower level of total-N than standard of KS (more than 0.09%). C/N ratio of six study sites except Shimwon1 was out of proper range (15:1~30:1). Average A.v. P (range) was $20.7mgkg^{-1}$ (4.8~63.1), less than other abandoned coal mine fores rehabilitation areas in Mungyong City, and Hwasun-gun. TOC, total N and A.v. P increased with elapsed time from forest rehabilitation, while other soil properties did not show distinct pattern. Betula platyphylla was planted in Samkwang and Sinsung where soil pH was less than KS standard. Because the growth of Betula platyphylla can be limited in acid soil, it is necessary to neutralize soil pH to proper level with some soil amendment such as lime or shell of oyster. Furthermore, TOC, total-N and A.v. P in early stage of forest rehabilitation showed lower level than proper to vegetation growth. Therefore it needs continuous monitoring of soil characteristics and fertilization for vegetation growth and influx from surrounding forest in early stage of rehabilitation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.419-420
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• 2008

In this study, high quality (Al,N)-codoped p-type ZnO thin films were obtained by DC magnetron sputtering. The film on buffer layer grown in 80% $N_2$ ambient shows highest hole concentration of $2.93\times10^{17}cm^{-3}$. The films show hole concentration in the range of $1.5\times10^{15}$ to $2.93\times10^{17}cm^{-3}$, resistivity of 131.2 to 2.864 $\Omega$cm, mobility of 3.99 to 31.6 $cm^2V^{-1}s^{-1}$. The films on Si show easier p-doping in ZnO than those on buffer layer. The film on Si shows the highest quality of optical photoluminescence (PL) characteristics. The donor energy level $(E_d)$ of (Al,N)-codoped ZnO films is about 50 meV and acceptor energy level $(E_a)$ is in the range of 63 to 71 meV. It will help to improve p-type ZnO films.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.2
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• pp.98-107
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• 1983

This experiment was carried out to determine the optimum fertilizer level of N-P-K for maximum yield of grasses at hill-land pasture. The pasture species tested were orchardgrass, tall fescue, alfalfa and ladino clover. The results are summarized as follows: 1. The difference in yield of treatment 1, 2, and 4, 5 was significant at the 5% level. In other word, alfalfa yields from 6-30-30 kg/10a and 6-40-30 kg/10a (N-P-K) application were significantly increased over the yields from 4-20-20 kg/10a and 4-30-20 kg/10a (N-P-K). In observing the yield from the treatment 5 where 10 kilograms of phosphate was additionally applied over the treatment 4, it was increased in yield but failed to show statistical significance. With these results, the most optimum rates of N-P-K for alfalfa production are 6-30-30 kg/10a. 2. Ladino clover showed the highest yield at treatment 6 with statistic significance at the 1 percent level over the other treatments. Therefore, NPK rates of 6-30-40 kg/10a would be the most optimal rates for maximum production of ladino clover. 3. Orchard grass yield showed significance at the 1 percent level among other treatments except treatment 3 and 4. The highest yield was also shown at treatment 6 where NPK rates applied 40-30-40 kg/10a. 4. Tall fescue yield showed high significance at the 1 percent except treatments between 2 and 3, 5 and 6. The highest yield was observed at treatment 6 where NPK was applied 40-30-40 kilograms per 10a. 5. Nitrogen content of dry matter was 0.91-1.05% in 20 kg of N and 1.05-1.26% in 30-40 kg of N per 10a. The absorption rate of nitrogen applied was 23-31% regardless of the nitrogen level. Potash content of dry matter was increased in accordance with increasing K rates. 6. The gross income was the highest on the N-P-K application of 4-20-30 kg/10a in alfalfa and ladion clover, 40-30-40 kg/10a in orchardgrass and 30-20-20 kg/10a in tall fescus.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.3
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• pp.199-204
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• 2014

We conducted a short-term incubation experiment in order to understand the effect of the salinity of reclaimed coastal soils on nitrogen mineralization of livestock manure compost (LMC). Two soils with the same soil texture but different EC levels were collected from the same field. These samples were treated with 0%, 1%, 2%, and 3% of LMC by weight basis and incubated at $25^{\circ}C$ to observe changes in inorganic N contents, pH, and dehydrogenase activity with respect to time. As a result, regardless of the soil EC level, as the LMC increased, the total content of the inorganic N ($NH_4{^+}+NO_3{^-}$) increased. Difference in the soil EC level did not affect N mineralization of LMC greatly. The soil EC had negligible effect on the dehydrgenase activity as with the case of inorganic nitrogen. The $NH_4{^+}$ contents remained very low throughout the experimental period starting from the first week of incubation. We believe this is due to the high pH level (pH 7.9 and pH 8.3) of the original soils leading to ammonia volatilization. On the other hand the $NO_3{^-}$ content maintained high level as the LMC treatment level increased and reached maximum at the third week. The pH of the soil during incubation period decreased as the $NO_3{^-}$ contents increased and increased slightly after three weeks. The rise of pH level is believed to be from the $NO_3{^-}$ absorption for immobilization by microbes. In conclusion, the high soil $EC_{1:5}$ level of $12dS\;m^{-1}$ conducted in this experiment did not affect the growth in terms of soil microbes involved in N mineralization of LMC.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.173-177
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• 2006

Terminal buds and young leaves of Kalopanax pictus are in a great demand as a edible vegetable. Its bark of stems and roots have been used as the resources of folk medicine in Korea. Recently, attempts to cultivate the plant have being tried in farms and mountain villages. This study was conducted to determine effect of inorganic elements on seedlings growth of K. pictus. Levels of inorganic elements in the leaves were variable based on macro and micro inorganic elements. Among the inorganic elements in the leaves of K. pictus seedlings, level of N was high, while other ions were low in the order of K, Ca, P, Mg, Mn, Fe and Zn. A highly significant correlations between the seedling growth and the level of N, P, K, and Na in the leaves, while a low positive significant correlations between the growth and the level of either Mg or Mn and no significant correlations between the growth and the level of Ca, Fe, Cu, and Zn. The most affecting inorganic ion on the seedling growth was N, and followed by the order of K, P, Mg, Mn and Na.

• Journal of the Korean Society of Food Culture
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• v.35 no.5
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• pp.483-492
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• 2020

Dietary components can modulate stress, inflammatory indicators, and health risk. This study examined the relationship among diet, metabolic disease risk, and perceived stress in Korean adult females using the 2017-2018 Korea National Health and Nutrition Examination Survey. A total of 4,353 adult women aged 19-64 years were classified into four groups according to perceived stress level: very high stress group (VHSG, n=225), high stress group (HSG, n=1,079), moderate stress group (MSG, n=2,532), and low stress group (LSG, n=517). Data collection included the sociodemographics, anthropometrics, blood profile, and dietary survey. After adjusting for covariates, those in the VHSG had a higher body mass index (p=0.013) and obesity rate (p=0.053) with a shorter sleep time than the LSG group. The VHSG also tended to have a higher plasma LDL-cholesterol, hsC-reactive protein and lower levels of HDL-cholesterol, vitamin A, and vitamin E than the low stress group. High stress subjects demonstrated increased breakfast skipping frequency (p<0.0001), decreased fiber intake (p=0.001), potassium (p=0.041), and vitamin A (p=0.011) than the low stress ones. Therefore the perceived stress level was associated with the inflammatory indicators, obesity, and lack of anti-inflammatory or antioxidant nutrients. The dietary components may be an important mediator of stress and metabolic disease.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.41-46
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• 2004

The influence of pollutant loads on the water quality in Jeongeupcheon of Dongjin river was evaluated from Jan. 2002 to Dec. 2003 for two years. The range of pH in water was $6.87{\sim}7.53$. The EC level in upstream ranged from 83 to $95\;{\mu}s/cm$ with the highest value in autumn. The BOD level in upstream rang ed from 0.61 to 1.27 mg/L, which would be I grade according to water quality criteria by Ministry of Environment, but that in downstream was III grade. The average T-N level in midstream ranged from 6.10 to 10.84 mg/L which was the highest values throughout the stretch of the river. The average T-P levels ranged from. 0.41 to 0.98 mg/L Jeongeupcheon was suitable for the agricultural usage based upon one year analysis of river water quality. The effluent loads of BOD was high in midstream (J4) with 553 kg/day. The major sources of T-N loads were livestock, population, land use, and industry in order. The effluent loads of T-N was high in J4 by population and industry while that of T-N was high in J5 and J6 by livestock and land use. The delivered loads of T-N was high in downstream The delivered loads of T-P was low as compared with those of BOD and T-N. The delivery ratio of T-N ranged from 6 to 38%.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.136-142
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• 1985

For better grassland development in the forest, this field experiment was carried out to investigate the effect of thirteen different fertilizer levels of nitrogen(N), phosphorus ($P_2O_5$) and potassium ($K_2O$) on the botanical composition, growth and dry matter yield of grass-clover mixtures grown under trees with 40-50% of shading level. This experiment was arranged as a randomized block design with replications, and performed on the experimental field in the suburban forest of Suweon in 1984. The results obtained are summarized as follows: 1. Plant height and cover degree of grasses found to be high with 28 and 42kg N fertilizer per 10a, while those were the lowest with zero and N-zero fertilizer levels. The degree of bare land after the fourth cut was also high in the low N level. 2. A significant higher degree of leaf green and chlorophyll content of leaf blade was observed in the plot of 28 and 42 kg N per 10a when compared with low N fertilizer plot. However, leaf decay and plant type of grasses tended to be a little poor as the high N was applied. 3. the regrowth plant length and dry weight of grasses after the first cut increased significantly with 28 and 42 kg N fertilizer. However, those showed slightly increased regrowth in the plot of zero and N-zero fertilizer levels. 4. The dry matter yield of grasses was higher with 28 and 42 kg N than that of low N fertilizer level. Higher yields were obtained in the plot of standard ($N-P_2O_5-K_2O$=28-20-24 kg/10a), 50% increase of $N,P_2O_5K_2O$ and N-50% increase, although there were no significant differences among three fertilizer levels. 5. Growth, botanical composition, regrowth and yield of grasses grown under pine trees were significantly influenced by N fertilizer level, regardless of $P_2O_5\;and\;K_2O$. The fertilizer level of $N-P_2O_5-K_2O$ was 28-20-24 kg per 10a for more forage production in the forest. Considering economic yield in this study, however, the optimum fertilizer level of N, $P_2O_5\;and\;K_2O$ was suppose to be 21-28, 10-15, and 12-18kg per 10a, respectively.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.307-313
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• 1997

he photoconductive gain mechanism in amorphus silicon devices was investigated in connection with applications to radiation detection. Various device types such as p-i-n, n-i-n and i-i-p-i-n structures were fabricated and tested. Photoconductive gain was measured in two time scales : one for short pulses of visible light(<$1{\mu}sec$) which simulate the transit of energetic charged particles or ${\gamma}$-rays, and the other for rather long pulses of light(1msec) which simulate x-ray exposure in medical imaging, We used two definitions of phtoconductive gain : current gain and charge gain which is an integration of the current gain. We obtained typical charge gains of 3~9 for short pulses and a few hundreds for long pulses at a dark current density level of 10mA/$cm^2$. Various gain results are discussed in terms of the device structure, applied bias and dark current density.

• BMB Reports
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• v.40 no.6
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• pp.979-985
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• 2007

Induction of growth hormone (GH) by Glycyrrhizae Radix (GR), one of the most popular herbal medicine, and its major ingredients were studied in rat pituitary cells in vitro and in vivo assay. The MeOH extract and the n-hexane (HX) fraction of GR induced rat GH (rGH) release up to 1.89 times ($0.34{\pm}0.04 nM$) and 4.59 times ($0.83{\pm}0.03 nM$), compared to the basal level (p < 0.05). Among many ingredients isolated and purified from GR both glycyrrhetinic acid and glycyrrhizin induced significantly rGH release compared to the control (p < 0.05). After an intravenous injection of rat growth hormone releasing hormone (rGHRH) ($10{\mu}g$/kg) as positive control, in SD rats, $T_{max}$ of plasma rGH level was 10 min, $C_{max}$ was $3.84{\pm}0.01 nM$ (n = 3), and enhanced plasma rGH level returned to the baseline in 90 min. Both $AUC_{0-90}$ (area under the curve) of plasma rGH level after HX fraction and that after rGHRH administration were increased significantly from the basal level, respectively (p < 0.01). In conclusions, HX fraction is the most active fraction of MeOH extract of GR in rGH induction.